Ask Questions, Get Answers

Want to ask us a question? Click here
Browse Questions
Home  >>  JEEMAIN and AIPMT  >>  Physics  >>  Class12  >>  Electromagnetic Waves
0 votes

A plane electromagnetic wave in the visible region is moving along the $z$ direction. The frequency of the wave is $0.5 \times 10^{15}Hz$ and the electric field at any point is varying sinusoidally with time with amplitude of $1\: V/m$. Calculate the average values of densities of the magnetic field.

$\begin {array} {1 1} (a)\;2.21 \times 10^{-12}J/m^2 & \quad (b)\;2.21 \times 10^{-2}J/m^2 \\ (c)\;22.1 \times 10^{-12}J/m^2 & \quad (d)\;22.1 \times 10^{-2}J/m^2 \end {array}$

Can you answer this question?

1 Answer

0 votes
The average value of magnetic field density is given by
$ = \large\frac{B_o^2}{ 4 \mu_o}$$ = \large\frac{1}{4}$$ \large\frac{E_o^2}{ \mu_oc^2}$$ = \large\frac{0.25 \times1}{ 4 \pi \times 10^{-7} \times (3 \times 10^8)^2} $$= 2.21 \times 10^{-12} J/m^2$
Ans : (a)


answered Mar 1, 2014 by thanvigandhi_1
edited Oct 8, 2014 by thagee.vedartham

Related questions

Ask Question
student study plans
JEE MAIN, CBSE, AIPMT Mobile and Tablet App
The ultimate mobile app to help you crack your examinations
Get the Android App